WARNS=5 breaks with old gcc

As can be seen on the NetBSD/vax -current builds, WARNS=5 does not properly
work with gcc 4.1.

Is the following patch correct?

RCS file: /cvsroot/src/share/mk/bsd.sys.mk,v
retrieving revision 1.215
diff -u -r1.215 bsd.sys.mk
--- bsd.sys.mk  20 Mar 2012 21:48:20 -0000      1.215
+++ bsd.sys.mk  24 Jun 2012 08:26:25 -0000
 <at>  <at>  -60,7 +60,7  <at>  <at> 
 CXXFLAGS+=     ${${ACTIVE_CXX} == "gcc":? -Wno-non-template-friend -Wno-pmf-conversions :}
 .endif
 .if ${WARNS} > 3 && (defined(HAVE_GCC) || defined(HAVE_LLVM))
-.if ${WARNS} > 4
+.if ${WARNS} > 4 && (!defined(HAVE_GCC) || ${HAVE_GCC} >= 45)
 CFLAGS+=       -Wold-style-definition
 .endif
 CFLAGS+=       -Wsign-compare -Wformat=2

Martin